Tesselation Shader based Subdivision Surface rendering of Polymeshes

This is a feature request for a (possibly tesselation shader based) rendering mode for polyline meshes.

A Catmull-Clark refinement operator should be applied with a configurable number of steps. Ideally, the smoothing operator should be configurable as well (bilinear, biquadratic, bicubic) but the most important one is definitely bilinear, so for a first version it's ok if this is fixed.

What's important is that wireframe rendering as well as "edges (colored)" must still work in the sense that the line segments of the wireframe get refined and smoothed but the wireframe mesh does not become finer.